1. Field of the Invention
The present invention relates to an exhaust gas purification device of an engine.
2. Description of the Related Art
Known in the art is a vehicle provided with a so-called hybrid type power generation device designed to generate the drive power of the vehicle by a combination of an output torque of an internal combustion engine and an output torque of an electric motor, where a catalyst arranged in an engine exhaust passage is rapidly warmed by using the electric motor to the maximum extent as the drive power of the vehicle, operating the internal combustion engine independently from the running of the vehicle at that time, making the air-fuel ratio for warming the catalyst the stoichiometric air-fuel ratio, and greatly delaying the ignition timing (see xe2x80x9c87. The Cleanest Car e no Chosen, Sono 2xe2x80x94Teerupaipuemisshon no Teigenxe2x80x9d (87. Challenge of the Cleanest Car, Part 2xe2x80x94Reduction of Tail Pipe Emission), Society of Automotive Engineers of Japan Preprints No. 19-00, No. 20005/88.)
The internal combustion engine being used in such a vehicle is a gasoline engine. Therefore, since the temperature of the exhaust gas is high, once the catalyst is warmed, it is maintained in the warmed state during engine operation. Therefore, in this vehicle, the operation is specially controlled to warm up the catalyst only at the time of engine startup.
At the present time, however, the inventors etc. are working on the development of an exhaust gas purification device designed to continuously remove by oxidation particulate exhausted from an engine onto a particulate filter arranged in the engine exhaust passage. In this exhaust gas purification device, however, they found that the continuous oxidation removal action of particulate is only performed in a limited partial operating region of the engine operating region even after the particulate filter finishes being warmed up.
Therefore, in this exhaust gas purification device, it is necessary to specially control the operation so as to cause the oxidation removal action of the particulate to be continuously performed in order to get the particulate continuously removed by oxidation even after the particulate filter finishes being warmed up.
An object of the present invention is to provide an exhaust gas purification device designed to cause the oxidation removal action of particulate to be continuously performed as much as possible even when continuous oxidation removal action of particulate by oxidation is only performed at a partial engine operating region after the particulate filter finishes being warmed up.
According to a first aspect of the present invention, there is provided an exhaust gas purification device of an internal combustion engine in which a particulate filter for trapping particulate in an exhaust gas is arranged in an engine exhaust passage, deposited particulate on the particulate filter can be continuously removed by oxidation without being accompanied by occurrence of a luminous flame when performing continuous combustion under a lean air-flow ratio, and a continuous oxidation removal region of the deposited particulate is determined by a temperature of the particulate filter and an amount of exhausted particulate exhausted from the engine, wherein an electric power device able to generate vehicle drive power separate from the vehicle drive power of the engine and able to generate electric power from the engine is provided and a battery for supplying electric power for driving the vehicle to the electric power device and for being charged by the electric power generated by the electric power device is provided; and, after the particulate filter finishes being warmed up at the time of engine startup, when the temperature of the particulate filter falls below a temperature at which deposited particulate can be continuously removed by oxidation, an output torque of the engine is increased from a required torque so that the temperature of the particulate filter becomes a temperature at which deposited particulate can be continuously removed by oxidation and the amount of increase in output torque is consumed for the power generating action by the electric power device.
According to a second aspect of the present invention, there is provided an exhaust gas purification device of an internal combustion engine in which a particulate filter for trapping particulate in an exhaust gas is arranged in an engine exhaust passage, deposited particulate on the particulate filter can be continuously removed by oxidation without being accompanied by occurrence of a luminous flame when performing continuous combustion under a lean air-flow ratio, and a continuous oxidation removal region of the deposited particulate is determined by a temperature of the particulate filter and an amount of exhausted particulate exhausted from the engine, wherein an electric power device able to generate vehicle drive power separate from the vehicle drive power of the engine and able to generate electric power from the engine is provided and a battery for supplying electric power for driving the vehicle to the electric power device and for being charged by the electric power generated by the electric power device is provided; and, after the particulate filter finishes being warmed up at the time of engine startup, when the amount of exhausted particulate is greater than an amount of exhausted particulate at which the deposited particulate can be continuously removed by oxidation, an output torque of the engine is decreased from a required torque so that the amount of exhausted particulate becomes an amount at which the deposited particulate can be continuously removed by oxidation and the amount of decrease in output torque is compensated for by the vehicle drive power from the electric power device.
According to a third aspect of the present invention, there is provided an exhaust gas purification device of an internal combustion engine in which a particulate filter for trapping particulate in an exhaust gas is arranged in an engine exhaust passage, deposited particulate on the particulate filter can be continuously removed by oxidation without being accompanied by occurrence of a luminous flame when performing continuous combustion under a lean air-flow ratio, and a continuous oxidation removal region of the deposited particulate is determined by a temperature of the particulate filter and an amount of exhausted particulate exhausted from the engine, wherein after the particulate filter finishes being warmed up at the time of engine startup, at the time of steady engine operation, a continuous oxidation removal region of deposited particulate is formed in a limited partial operating region of the operating region of the engine; an electric power device able to generate vehicle drive power separate from the vehicle drive power of the engine and able to generate electric power from the engine is provided and a battery for supplying electric power for driving the vehicle to the electric power device and for being charged by the electric power generated by the electric power device is provided; and, after the particulate filter finishes being warmed up at the time of engine startup, when the output torque of the engine is lower than an output torque of the limited partial operating region, the output torque of the engine is increased from the required torque so that the output torque of the engine becomes the output torque of the limited partial operating region and the amount of increase in output torque is consumed for the power generating action of the electric power device.
According to a fourth aspect of the present invention, there is provided an exhaust gas purification device of an internal combustion engine in which a particulate filter for trapping particulate in an exhaust gas is arranged in an engine exhaust passage, deposited particulate on the particulate filter can be continuously removed by oxidation without being accompanied by occurrence of a luminous flame when performing continuous combustion under a lean air-flow ratio, and a continuous oxidation removal region of the deposited particulate is determined by a temperature of the particulate filter and an amount of exhausted particulate exhausted from the engine, wherein after the particulate filter finishes being warmed up at the time of engine startup, at the time of steady engine operation, a continuous oxidation removal region of deposited particulate is formed in a limited partial operating region of the operating region of the engine; an electric power device able to generate vehicle drive power separate from the vehicle drive power of the engine and able to generate electric power from the engine is provided and a battery for supplying electric power for driving the vehicle to the electric power device and for being charged by the electric power generated by the electric power device is provided; and, after the particulate filter finishes being warmed up at the time of engine startup, when the output torque of the engine is higher than an output torque of the limited partial operating region, the output torque of the engine is decreased from the required torque so that the output torque of the engine becomes the output torque of the limited partial operating region and the amount of decrease in output torque is compensated for by the vehicle drive power of the electric power device.
According to a fifth aspect of the present invention, there is provided an exhaust gas purification device of an internal combustion engine in which a particulate filter for trapping particulate in an exhaust gas is arranged in an engine exhaust passage, deposited particulate on the particulate filter can be continuously removed by oxidation without being accompanied by occurrence of a luminous flame when performing continuous combustion under a lean air-flow ratio, and a continuous oxidation removal region of the deposited particulate is determined by a temperature of the particulate filter and an amount of exhausted particulate exhausted from the engine, wherein an electric power device able to generate vehicle drive power separate from the vehicle drive power of the engine and able to generate electric power from the engine is provided, a battery for supplying electric power for driving the vehicle to the electric power device and for being charged by the electric power generated by the electric power device is provided, and estimating means for estimating the amount of deposited particulate on the particulate filter is provided; when it is estimated by the estimating means that the amount of deposited particulate on the particulate filter has exceeded a predetermined allowable amount, when the temperature of the particulate filter is lower than a temperature at which the deposited particulate can be continuously removed by oxidation, the output torque of the engine is increased from the required torque so that the temperature of the particulate filter becomes a temperature at which the deposited particulate can be continuously removed by oxidation and the amount of increase of the output torque is consumed by the power generating action of the electric power device.
According to a sixth aspect of the present invention, there is provided an exhaust gas purification device of an internal combustion engine in which a particulate filter for trapping particulate in an exhaust gas is arranged in an engine exhaust passage, deposited particulate on the particulate filter can be continuously removed by oxidation without being accompanied by occurrence of a luminous flame when performing continuous combustion under a lean air-flow ratio, and a continuous oxidation removal region of the deposited particulate is determined by a temperature of the particulate filter and an amount of exhausted particulate exhausted from the engine, wherein an electric power device able to generate vehicle drive power separate from the vehicle drive power of the engine and able to generate electric power from the engine is provided, a battery for supplying electric power for driving the vehicle to the electric power device and for being charged by the electric power generated by the electric power device is provided, and estimating means for estimating the amount of deposited particulate on the particulate filter is provided; when it is estimated by the estimating means that the amount of deposited particulate on the particulate filter has exceeded a predetermined allowable amount, when the amount of the exhausted particulate is larger than an amount of exhausted particulate at which the deposited particulate can be continuously removed by oxidation, the output torque of the engine is decreased from the required torque so that the amount of exhausted particulate becomes an amount at which the deposited particulate can be continuously removed by oxidation and the amount of decrease of the output torque is compensated for by the vehicle drive power of the electric power device.
According to a seventh aspect of the present invention, there is provided an exhaust gas purification device of an internal combustion engine in which a particulate filter for trapping particulate in an exhaust gas is arranged in an engine exhaust passage, deposited particulate on the particulate filter can be continuously removed by oxidation without being accompanied by occurrence of a luminous flame when performing continuous combustion under a lean air-flow ratio, and a continuous oxidation removal region of the deposited particulate is determined by a temperature of the particulate filter and an amount of exhausted particulate exhausted from the engine, wherein the internal combustion engine is an internal combustion engine where when an amount of inert gas in the combustion chamber increases, the amount of production of soot gradually increases and then peaks and where when further increasing the amount of inert gas in the combustion chamber, a temperature of the fuel and its surrounding gas at the time of combustion in the combustion chamber becomes lower than the temperature of production of soot and soot is no longer produced much at all; an electric power device able to generate vehicle drive power separate from the vehicle drive power of the engine and able to generate electric power from the engine is provided, a battery for supplying electric power for driving the vehicle to the electric power device and for being charged by the electric power generated by the electric power device is provided, estimating means for estimating the amount of deposited particulate on the particulate filter is provided, and switching means is provided for selectively switching between a first combustion where an amount of inert gas in the combustion chamber is larger than an amount of inert gas at which the amount of production of soot peaks and a second combustion where an amount of inert gas in the combustion chamber is smaller than the amount of inert gas at which the amount of production of soot peaks; and after the particulate filter finishes being warmed up, when it is estimated by the estimating means that the amount of deposited particulate on the particulate filter has exceeded a predetermined allowable amount, the second combustion is switched to the first combustion by the switching means and a torque difference between the engine output torque and the required torque is adjusted by the electric power device so that the required torque is given to the vehicle.
According to an eighth aspect of the present invention, there is provided an exhaust gas purification device of an internal combustion engine in which a particulate filter for trapping particulate in an exhaust gas is arranged in an engine exhaust passage, deposited particulate on the particulate filter can be continuously removed by oxidation without being accompanied by occurrence of a luminous flame when performing continuous combustion under a lean air-flow ratio, and a continuous oxidation removal region of the deposited particulate is determined by a temperature of the particulate filter and an amount of exhausted particulate exhausted from the engine, wherein the internal combustion engine is an internal combustion engine where when an amount of inert gas in the combustion chamber increases, the amount of production of soot gradually increases and then peaks and where when further increasing the amount of inert gas in the combustion chamber, a temperature of the fuel and its surrounding gas at the time of combustion in the combustion chamber becomes lower than the temperature of production of soot and soot is no longer produced much at all; an electric power device able to generate vehicle drive power separate from the vehicle drive power of the engine and able to generate electric power from the engine is provided, a battery for supplying electric power for driving the vehicle to the electric power device and for being charged by the electric power generated by the electric power device is provided, and switching means is provided for selectively switching between a first combustion where an amount of inert gas in the combustion chamber is larger than an amount of inert gas at which the amount of production of soot peaks and a second combustion where an amount of inert gas in the combustion chamber is smaller than the amount of inert gas at which the amount of production of soot peaks; and when a temperature of the particulate filter is lower than a temperature at which the deposited particulate can be continuously removed by oxidation and a representative value of charging expressing an amount of charging of the battery is lower than a set representative value, the output torque of the engine is increased from the required torque under the second combustion and the amount of increase of the output torque is consumed for the power generating action of the electric power device.
According to a ninth aspect of the present invention, there is provided an exhaust gas purification device of an internal combustion engine in which a particulate filter for trapping particulate in an exhaust gas is arranged in an engine exhaust passage, deposited particulate on the particulate filter can be continuously removed by oxidation without being accompanied by occurrence of a luminous flame when performing continuous combustion under a lean air-flow ratio, and a continuous oxidation removal region of the deposited particulate is determined by a temperature of the particulate filter and an amount of exhausted particulate exhausted from the engine, wherein the internal combustion engine is an internal combustion engine where when an amount of inert gas in the combustion chamber increases, the amount of production of soot gradually increases and then peaks and where when further increasing the amount of inert gas in the combustion chamber, a temperature of the fuel and its surrounding gas at the time of combustion in the combustion chamber becomes lower than the temperature of production of soot and soot is no longer produced much at all; an electric power device able to generate vehicle drive power separate from the vehicle drive power of the engine and able to generate electric power from the engine is provided, a battery for supplying electric power for driving the vehicle to the electric power device and for being charged by the electric power generated by the electric power device is provided, and switching means is provided for selectively switching between a first combustion where an amount of inert gas in the combustion chamber is larger than an amount of inert gas at which the amount of production of soot peaks and a second combustion where an amount of inert gas in the combustion chamber is smaller than the amount of inert gas at which the amount of production of soot peaks; when an amount of exhausted particulate is larger than an amount at which deposited particulate can be continuously removed by oxidation, the output torque of the engine is decreased from the required torque under the second combustion and the amount of decrease of the output torque is compensated for by the vehicle drive power of the electric power device; while when a temperature of the particulate filter becomes lower than the temperature at which the deposited particulate can be continuously removed by oxidation, the second combustion is switched to the first combustion and a torque difference between the output torque of the engine and the required torque is adjusted by the electric power device so that a required torque is given to the vehicle.
According to a 10th aspect of the present invention, there is provided an exhaust gas purification device of an internal combustion engine in which a particulate filter for trapping particulate in an exhaust gas is arranged in an engine exhaust passage, deposited particulate on the particulate filter can be continuously removed by oxidation without being accompanied by occurrence of a luminous flame when performing continuous combustion under a lean air-flow ratio, and a continuous oxidation removal region of the deposited particulate is determined by a temperature of the particulate filter and an amount of exhausted particulate exhausted from the engine, wherein the device comprises an NOx absorbent which is carried on the particulate filter, absorbs NOx when an air-fuel ratio of inflowing exhaust gas is lean, and releases the absorbed NOx when the air-fuel ratio of the inflowing exhaust gas is rich or the stoichiometric air-fuel ratio, an electric power device able to generate vehicle drive power separate from the vehicle drive power of the engine and able to generate electric power from the engine, and a battery for supplying electric power for driving the vehicle to the electric power device and for being charged by the electric power generated by the electric power device; after the particulate filter finishes being warmed up, when the temperature of the particulate filter falls below a temperature at which the deposited particulate can be continuously removed by oxidation, the output torque of the engine is increased from the required torque so that the temperature of the particulate filter becomes a temperature at which the deposited particulate can be continuously removed by oxidation and the amount of increase of the output torque is consumed for the power generating action of the electric power device; and, when NOx or SOx should be released from the NOx absorbent, the air-fuel ratio of the exhaust gas flowing into the NOx absorbent is temporarily changed from lean to rich.